Magnetic relay with special armature mounting means



1954 B. s. BENGTSSON 2,566,826

MAGNETIC RELAY WITH SPECIAL ARMATURE MOUNTING MEANS F iled June 21, 1951 2 Sheets-Sheet 1 3nventor BER TIL J BENGTJS ON Jan. '19, 1954 B. S. BENGTSSON MAGNETIC RELAY WITH SPECIAL ARMATURE MOUNTING MEANS Filed June 21, 1951 44 1 45 40 50 I a lb 70 in 2 Shee'ts-Sheex 2 h Qnventor BERT/L SBENGTJJON attorneys Patented Jan. 19, 1954 MAGNETIC RELAY WITH SPECIAL ARMA- TURE MOUNTING MEANS Bertil S. Bengtsson, Hartford, Conn., assignor to The Hart Manufacturing Company, Hartford, Conn., a corporation of Connecticut Application June 21, 1951, Serial No. 232,840

3 Claims.

new and unexpected advantages in operation and use.

It is a principal object of the present invention to provide an extremely fast acting relay and a relay which is exceedingly compact in construction. To this end it is an object of the invention to provide a unique construction of a relay employing the polarized relay principle of operation which is highly efficient in arrangement and operation of its parts, which reduces the number of air gaps to a minimum, which is fast and positive in action, which is inherently balanced, which may be readily adjusted and is sufficiently rugged to withstand sudden shock, which is simple and economical to fabricate, assemble and adjust, and which is of minimum size.

Other objects will be in part obvious, and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claims.

In the drawings:

Fig. 1 is a side view of an assembled relay with the cover housing in place, which relay comprises an exemplary embodiment of the present invention;

Fig. 2 is an enlarged fragmentary side view of the relay with the cover housing removed;

Fig. 3 is a view similar to Fig. 2 with the relay turned 90 degrees;

Fig. 4 is a top view of the relay with the cover housing removed;

Fig. 5 is a cross sectional view taken along the line 5-5 of Fig. 4;

Fig. 6 is a cross sectional view taken along the line 66 of Fig. 4;

Fig. 7 is a cross sectional view taken along the line 11 of Fig. 2;

Fig. 8 is a cross sectional view taken along the line 8-8 of Fig. 2;

Fig. 9 is a fragmentary side view of the relay with cover housing and adjusting screw bracket removed; and

Fig. 10 is a diagrammatic View showing the magnetic flux paths present during the operation of the relay.

Referring to the drawings, the relay shown is mounted on a base assembly I0 which includes a 2 conventional base plate ll having suitable connecting terminals [2 which, however, are electrically insulated from the base plate. Centrally of the base plate H is a tube is which is utilized for evacuating the relay of air and filling it with an inert gas. The tube It also has a positioning function as well as serving to hold the base assembly together as described hereinafter. Situated on the upper side of the base plate [I is an insulating disc 14 on which, in turn, is positioned a mounting bracket It. The mounting bracket, as best shown in Figs. 3 and 5, is provided with upwardly extending posts It at opposite sides thereof, the posts It being generally rectangular in cross section and being utilized for anchoring certain parts of the relay as will be described later. The central portion of the bracket 1 5 is recessed at H to receive an insulating washer H3. The upper end of the evacuation tube I3, previously referred to, is peened over the top of the insulating washer :8, thus securely fastening the base assembly together.

Secured to the side faces of posts l6, for example, by means of screws 2!! are a plurality of laminated core members 2 l. The core laminations 2|, as best shown in Fig. 9, are generally in the shape of a capital letter E, being provided with a vertical column 22 and three horizontal branches 23, 24, and 25, respectively. The core laminations 2| are preferably made in two different sizes, i. e. with lower horizontal legs 25 of different length. This permits the core laminations to be utilized facing each other without any air gaps between the base legs 25. This is accomplished by alternating core laminations of diiferent length legs so that they may be interfitted with the corresponding legs of the facing core laminations. If desired, the facing core laminations could be made in one piece but this would be disadvantageous because it would complicate the winding of the coils referred to hereinafter and also would interfere with the adjustment feature.

The base legs 25 of the core laminations 2| are inserted through coil bobbins 30 on which are wound conventional coils 3|. The result is that each set of facing core laminations' 2! is provided with its own coil 3!. The coils are connected in parallel magnetically (so that the adjacent pole faces are the same) for the reason explained more fully hereinafter, and therefore function in the same manner as though a single coil were utilized. Plural coils are utilized primarily because of space limitations and for more efiicient operation. After the coils SI and core laminations 25 are assembled, as described, the core laminations are then fastened at the four corners to the posts N3 of the mounting bracket 15, as clearly shown in the drawings, such by screws 2b as previously mentioned.

There is then inserted between the facing pairs of upper legs 23 and 24 of the core laminations 2! an armature assembly 4b which includes an armature ll which is generally in the form of a square metallic plate having horizontal slots 42 milled on opposite sides thereof. Disposed centrally of the armature are projections 43 by means of which the armature may be fastened to a hinge id. The hinge 44 is generally in the shape of a Roman numeral II as best shown in Fig. and is preferably composed of thin flexible spring metal. The upper and lower bars of the spring hinge are fastened centrally thereof to the projections at, such as by means of rivets 45.

The projecting ends of the spring hinge 44 are then clamped between two armature brackets 59 which also are generally shaped like the hinge Aid, 1. e. like the Roman numeral II in vertical cross section, and which ar formed with the upright legs thereof projecting inwardly to engage against the projecting side legs of the spring hinge M as best shown in Fig. 4. The armature assembly thus clamped between. the two armature brackets is then slid between the core laminations and the bases of the armature brackets iitl are then fastened to the opposite posts 16 of the mounting bracket i5 by means of screws 5%. In this way it will be seen the armature Al is disposed vertically between the upper projecting legs of the core laminations 2| and is mounted to swing about a vertical axis, although biased by the action of the spring hinge to an at rest position intermediate the core laminations.

There is next provided a contact finger bracket preferably formed of electrically insulating material and having secured thereto and extend ing inwardly through a central aperture 56 a pair of contact fingers 5'! which are formed of resilient metal. The contact fingers 5'! may be fastened to the bracket 55 by means of rivets 5 In the embodiment shown, the bracket 55 also provided with metallic spacer ring 53. The flexible contact fingers 5? are inserted alongside the armature and the bracket 55 is then fastened to the side of one of the armature brackets by means of screws 59.

On the opposite side of the relay from the contact finger bracket there is provided an adjusting screw bracket iii). The bracket 5'? is basically metallic rectangular plate vertically slotted at the bottom edge, as shown at iii. The bracket is is tapped horizontally from opposite sides shown at t2 to receive adjusting screws E3. The adjusting screws are adapted to engage against the extrem ties of the contact fingers and thus adjustably position them relative to the armature 4'5. The bracket '50 is also tapped vericallv as shown at E4 to receive lockscrews 65 which are utilized to fix the position of the adiusting screws 63 after the contact have been ad usted. The bracket lid is secured to the outer face of the ad acent armature bracket so by means of screws 66.

The contact fingers iii are provided with contact points 52 which are adapted to be engaged alternately by a contact point 53 on the armature M, depending on the direction of swing of the armature. Suitable connections (not shown) may be made, of course, between terminals i2 and the contact fingers 51, as well as between one of the terminals i2 and the armature brackets 5%. In the specific embodiment shown, for simplicity of presentation, the relay shown in the drawings is of the single-pole, double-throw type. It will be noted, however, that even in a singlepole relay the armature 4| is preferably provided with a second contact point 53a which is provided primarily to balance the weight of the contact point 53. As will be understood, the coils 3! are also connected to terminals l2 in the usual manner.

When assembling the relay, the next step is the insertion of two permanent magnets 10 and ll which are preferably of high coercive strength material, such as magnets formed from Alnico or the like. The magnets 10 and "H are preferably of equal magnetic strength and are inserted between the upper portions of the core laminations 2| with like poles adjacent.

The relay is now completely assembled and,

after all adjustments are made to balance the relay, the various fastening screws referred to are turned down to fix the relay parts in adjusted position. The contact fingers 51 may then be adjusted by means of setscrews 63 which, in turn, are locked by means of screws 65. Following this, the relay may be enclosed by a housing cover 15 which takes over the top of the relay and forms an air-tight connection with the base assembly ill. After evacuation of the air content of the relay and replacement with inert gas through the tube 13, the latter is pinched oil and the relay is ready for operation.

It thus will be seen that there is provided a relay which is simple and easy to fabricate and assemble. Set it includes an armature which is centrally hinged for swinging movement and which is completely balanced for such movement in response to the magnetic field created by flux lines emanating through the four projections of the core laminations (opposite pairs of the upper legs thereof) which are located at substantially the four corners of the armature. Referring to the diagrammatic view in Fig. 10, it will be seen that the relay is in balance so long as the coils 3| are not energized. The effective flux path, due to the permanent magnets alone, is shown by solid arrows having the reference numeral Bil. Inasmuch as the permanent magnets 10 and H are situated with like poles adjacent, the flux lines will oppose each other and thus balance at one side of the armature 4| (the north side of the permanent magnets) and will travel through the armature and emanate therefrom at a the opposite side to the south poles of the permanent magnets in opposite directions and thus again are in balance. However, when the coils 3! are energized, there is superimposed on the flux path pattern just previously described additional flux lines, as shown by dot-and-dash arrows 8|. As previously mentioned, the coils 3| are connected in parallel (magnetically) and for purposes of illustration it is assumed that the coils 3! are energized so that the north pole is at the lefthand side, as viewed in Fig. 10. The result is that flux lines are added which unbalance the system, being additive between the armature and the core laminations at the lower lefthand corner and at the upper righthand corner, but being in opposition at the lower righthand corner and upper lefthand corner. This unbalance causes the armature to swing, as shown by heavy arrows 82. If the direction of the current inthe coils .31 were reversed, of course the opposite condition wouldoccurand the swing would take place in the opposite direction. The diagram shows the flux paths as though there were only one set of the core branches or projections 23 or 24, it being understood that the paths through both are the same.

As a result of the construction shown, it has been found that the action of the relay is exceedingly fast with the result that the relay is particularly useful with precision instruments where time delays in actuation are critical. Furthermore, the only air gaps in the magnetic system of the relay occur at the armature so that the relay operates very efficiently and requires comparatively small electrical force for operation. Furthermore, the relay is extremely compact and accomplishes the fast action and efficient operation in a minimum of space.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim:

1. A polarized relay comprising an armature, a hinge engaging the armature at points on opposite edges thereof to mount said armature for swinging movement about a central axis extending through said points, a pair of core members disposed, respectively, at opposite sides of the hinge, each of said core members having spaced apart fingers projecting toward opposite faces of the armature adjacent the opposite edges thereof, fixed contacts situated in the space between the fingers mounted adjacent one edge of the armature, a contact on the armature cooperating with said fixed contacts, a pair of permanent magnets disposed opposite to opposite sides of the armature with like poles opposite each other located between and engaging the core members, and a coil winding on the core members.

2. A polarized relay comprising a plate-like armature, a spring hinge fastened to the midpoint of opposite edges of the armature to permit swinging movement of the armature about a central axis extending through said midpoints, a pair of permanent magnets disposed in parallel arrangement on opposite sides but spaced from the armature with like poles adjacent, a pair of core members each comprising a generally U-shaped base and two pairs of spaced apart fingers, means for positioning the core members against the adjacent poles of the permanent magnets with the spaced apart fingers projecting toward the opposite edges of the opposite faces of the armature, a coil winding .on the base of each core member, a pair of fixed contacts on opposite sides of the armature between the core fingers, and a cooperating contact point on the armature.

3. A polarized relay comprising a generally rectangular plate-like armature, a spring hinge fastened to the midpoint of opposite edges of the armature for mounting the armature for swinging movement about a central axis extending through said midpoints, a pair of permanent magnets disposed in parallel arrangement with like poles adjacent on opposite sides but spaced from the armature, a core on each side of the hinge and in contact with the adjacent like pole faces of the magnets, each core comprising two pairs of spaced apart fingers projecting toward the opposite faces of the armature adjacent the opposite edges thereof and a flux carrying loop between said fingers, a coil winding on the loop of each core, a mounting bracket disposed on the outer side of one core member, contact fingers extending inwardly between the core fingers from said bracket, a second bracket disposed on the outer side of the other core member, and means on the second bracket for adjusting the position of the contact fingers relative to the armature.

BERTIL S. BENGTSSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,541,618 Brown June 9, 1925 2,412,123 Carpenter Dec. 3, 1946 2,443,784 Bullen et al June 22, 1948 2,454,973 Mason Nov. 30, 19 2,473,939 Clark June 21, 1949 2,526,804 Carpenter Oct. 24, 1950 2,559,399 Carpenter July 3, 1951 

